Antoine Henri Becquerel (born December 15, 1852 in Paris, France), known as Henri Becquerel, was a French physicist who discovered radioactivity.
Lycée Louis-le-Grand, Paris, France
Henri Becquerel began his education by attending the Lycée Louis-le-Grand school, a preparatory school in Paris.
École Polytechnique, Palaiseau, France
Becquerel went to École Polytechnique from 1872 to 1874.
École des Ponts et Chaussées, Champs-sur-Marne, France
Becquerel attended the École des Ponts et Chaussées (1874-1877), where he received his engineering training.
University of Paris, Paris, France
In 1888 Becquerel acquired the degree of Docteur-ès-sciences from the University of Paris.
Antoine H Becquerel (1852-1908) was a French scientist renowned for his work and subsequent discovery into the evidence of radioactivity for which he was awarded a Nobel Prize.
Becquerel and the experiment with the magnet.
French Physicist Henri Becquerel
Henri Becquerel, French physicist
Becquerel and the consorts Curie.
Henri Becquerel, French physicist
Henri Becquerel on the left with Pierre and Marie Curie.
1900
Becquerel received the Rumford Medal for his discovery of the radioactivity of uranium.
1900
Becquerel was made an Officer of the Legion of Honour.
1903
Becquerel received the Nobel Prize for physics in 1903 “for his discovery of spontaneous radioactivity.”
1900
Becquerel received the Rumford Medal for his discovery of the radioactivity of uranium.
1900
Becquerel was made an Officer of the Legion of Honour.
1903
Becquerel received the Nobel Prize for physics in 1903 “for his discovery of spontaneous radioactivity.”
Henri Becquerel, French physicist
Antoine H Becquerel (1852-1908) was a French scientist renowned for his work and subsequent discovery into the evidence of radioactivity for which he was awarded a Nobel Prize.
Henri Becquerel, French physicist
Becquerel and the experiment with the magnet.
French Physicist Henri Becquerel
Henri Becquerel, French physicist
Image of Becquerel's photographic plate that was fogged by exposure to radiation from uranium salts. The shadow of a metal Maltese Cross placed between the plate and the uranium salts is clearly visible.
Becquerel and the consorts Curie.
Henri Becquerel, French physicist
Henri Becquerel on the left with Pierre and Marie Curie.
Lycée Louis-le-Grand, Paris, France
Henri Becquerel began his education by attending the Lycée Louis-le-Grand school, a preparatory school in Paris.
École Polytechnique, Palaiseau, France
Becquerel went to École Polytechnique from 1872 to 1874.
École des Ponts et Chaussées, Champs-sur-Marne, France
Becquerel attended the École des Ponts et Chaussées (1874-1877), where he received his engineering training.
University of Paris, Paris, France
In 1888 Becquerel acquired the degree of Docteur-ès-sciences from the University of Paris.
Antoine César Becquerel (7 March 1788 – 18 January 1878) was a French scientist and a pioneer in the study of electric and luminescent phenomena.
French Physicist Jean Becquerel
https://www.amazon.com/Recherches-Sur-LAbsorption-Lumiere-Propositions/dp/1168367727/?tag=2022091-20
1888
chemist engineer physicist scientist
Antoine Henri Becquerel was born in Paris on December 15, 1852, a member of a distinguished family of scholars and scientists. His father, Alexander Edmond Becquerel, was a Professor of Applied Physics and had done research on solar radiation and on phosphorescence, while his grandfather, Antoine César, had been a Fellow of the Royal Society and the inventor of an electrolytic method for extracting metals from their ores.
Henri Becquerel began his education by attending the Lycée Louis-le-Grand school, a preparatory school in Paris. Then he went to École Polytechnique (1872-1874) and after that to the École des Ponts et Chaussées (1874-1877), where he received his engineering training. In 1888 he acquired the degree of Docteur-ès-sciences from the University of Paris.
After the graduation from the École des Ponts et Chaussées, Becquerel entered the Administration of Bridges and Highways with the rank of ingénieur. Before the end of his schooling, he had begun both his private research (1875) and his teaching career (1876) as répétiteur at the Polytechnique. Becquerel then succeeded to the post of aide-naturaliste, which his father had hitherto held at the Museum, and from then on, his professional life was shared among the Museum, the Polytechnique, and the Ponts et Chaussées.
Becquerel’s early research was almost exclusively optical. His first extensive investigations (1875-1882) dealt with the rotation of plane-polarized light by magnetic fields. He turned next to infrared spectra (1883), making visual observations by means of the light released from certain phosphorescent crystals under infrared illumination. He then studied the absorption of light in crystals (1886-1888), particularly its dependence on the plane of polarization of the incident light and the direction of its propagation through the crystal. With these researches, Becquerel obtained an election to the Academy of Sciences (1889), after two preparatory nominations (1884, 1886), in the second of which he polled twenty of the fifty-one votes. He had in the meantime been promoted to ingénieur de première classe in the Ponts et Chaussées.
With his doctorate achieved, Becquerel became substantially inactive in research. In 1891 he succeeded two chairs of physics, at the Conservatoire National des Arts et Métiers and at the Museum. In the same year, Alfred Potier withdrew from active teaching because of illness, and Becquerel took over his lectures in physics at the École Polytechnique. Two years later ( 1894) he became ingénieur en chef with the Ponts et Chaussées and the next year (1895) was named to succeed Potier at the Polytechnique.
Thus the beginning of 1896 found Becquerel, at the age of forty-three, established in rank and responsibility, his years of active research behind him and everything for which he is now remembered still undone. In the very opening days of the year, Roentgen had announced his discovery of X rays by a mailing of preprints and photographs, but Becquerel’s personal knowledge of the discovery dates to 20 January, when two physicians, Paul Oudin, and Toussaint Barthélemy, submitted an X-ray photograph of the bones of a living hand to the Academy. From Henri Poincaré, who had received a preprint, Becquerel learned that in Roentgen’s tubes the X rays arose from the fluorescent spot where a beam of cathode rays played on the glass wall. Thus a natural, if perhaps not plausible, inference arose that the visible light and invisible X rays might be produced by the same mechanism and that X rays might accompany all luminescence.
On 24 February 1896, he reported to the Academy that fluorescent crystals of potassium uranyl sulfate had exposed a photographic plate wrapped in the black paper while they both lay for several hours in direct sunlight. On 2 March he reported comparable exposures when both crystals and plate lay in total darkness. By his working hypothesis, that would have been impossible because the luminescence of potassium uranyl sulfate ceases immediately when the ultraviolet radiation that excites it is withdrawn. One might speculate, nevertheless, that the penetrating rays persisted longer than the visible fluorescence when their common excitation was cut off. Becquerel did so, conscientiously condemned the speculation as unjustified, and then proceeded to act upon it.
Becquerel showed that, like X rays, the penetrating rays from his crystals could discharge electrified bodies (in modern terms, could ionize the air they passed through). He found evidence to suggest that the rays were refracted and reflected like visible light, although later he attributed these effects to secondary electrons ejected from his glass plates and mirrors. Nevertheless, he devoted a substantial effort to searching out the radiation that had first excited his penetrating rays. He kept some of his crystals in darkness, hoping that their pent-up energy might dissipate itself and make them ready for excitation. He tried other luminescent crystals and found that only those containing uranium emitted the penetrating radiation.
Becquerel tried ingeniously but unsuccessfully to release the energy of uranyl nitrate by warming its crystals in darkness until they dissolved in their own water of crystallization. He tested nonluminescent compounds of uranium and found that they emitted his penetrating rays. Finally, he tried a disk of pure uranium metal and found that it produced penetrating radiation three to four times as intense as that he had first seen with potassium uranyl sulfate.
With this last announcement, on 18 May, Becquerel’s discovery of radioactivity was complete, although he continued with ionization studies of his penetrating radiation until the following spring. What he had accomplished at the most general level was to establish the occurrence and the properties of that radiation, so that it could be identified unambiguously. Of more importance, he had shown that the power of emitting penetrating rays was a particular property of uranium.
However, the implications of this second conclusion were by no means clear at the time. Becquerel characterized his own achievement as the first observation of phosphorescence in a metal. His immediate successors, G. C. Schmidt and Marie Curie, started with quite conventional views about the rays and came only gradually to realize that such radiation might also be emitted by other elements. Both then searched among the known elements, finding that only thorium was also a ray-emitter. Marie Curie and her husband, Pierre, pushed on to search for unknown elements with the same property, however, and so discovered polonium and radium. With these discoveries, the field of radioactivity (a term that the Curies coined) was fully established.
Nothing that Becquerel subsequently accomplished was as important as this discovery, by which he opened the way to nuclear physics.
Nevertheless, there were two other occasions on which he stood directly on the path of history: when he identified electrons in the radiations of radium (1899-1900) and when he published the first evidence of a radioactive transformation (1901).
Marie Curie’s work, which attracted Becquerel’s attention, brought the Curies within the circle of his acquaintance and turned him back to radioactive studies. He became the intermediary through whom their papers reached the Academy, and they lent him radium preparations from time to time. Toward the end of 1899 (his first report is dated 11 December), he began to investigate the effects on the radiation from radium of magnetic fields in various orientations to the direction of its propagation (in modern terms, the magnetic deflection of the beta rays from short-term decay products in equilibrium with the radium). In this work, he united two descriptive traditions, the magneto-optics of his own experience and a line of qualitative studies of the discharge of electricity through gases. He soon moved from these to J. J. Thomson’s more radical program of quantitative observations on collimated beams, in which Thomson had shown ( 1897) that the cathode rays were corpuscular and consisted of streams of swiftly moving, negatively charged particles whose masses were probably subatomic. By 26 March 1900, Becquerel had duplicated those experiments for the radium radiation and had shown that it too consisted of negatively charged ions. Thus Thomson’s “corpuscles” (electrons) constituted a part of the radiations of radioactivity.
In 1903 the Nobel Prize for physics was divided between Henri Becquerel and Pierre and Marie Curie. It was an appropriate division. Becquerel’s pioneer investigations had opened the way to the Curies’ discoveries, and their discoveries had validated and shown the importance of his.
On 31 December 1906, Becquerel was elected vice-president of the Academy of Sciences, serving in that capacity during 1907 and succeeding to the presidency in 1908. On 29 June 1908, he was elected as one of the two permanent secretaries of the Academy, following the death of Lapparent. On confirmation by the president of the republic, he was installed in that office on 6 July, taking his seat beside Darboux, who had taught him mathematics nearly four decades before at the Lycée Louis-le-Grand.
In an assessment of Becquerel’s scientific powers, it should be noted that he had little taste for physical theories, either his own or those of others, and much of his research effort was dissipated on observations of no great significance. Against this, he displayed an admirable versatility in an experiment in unfamiliar as well as familiar fields. His greatest asset, however, was a strong, persistent power of critical afterthought. On those rare occasions when Becquerel did pursue a hypothesis, this critical power continually corrected his enthusiasms and redirected his line of investigation; so that, for example, while he persistently searched for X rays in phosphorescence, he managed to discover the inherent radioactivity of uranium.
Becquerel's greatest achievement was made due to his investigation of the newly discovered X-rays in 1896, which led to studies of how uranium salts are affected by light. By accident, he discovered that uranium salts spontaneously emit a penetrating radiation that can be registered on a photographic plate. Further studies made it clear that this radiation was something new and not X-ray radiation: he had discovered a new phenomenon, radioactivity.
For his scientific work, Becquerel earned several awards throughout his lifetime. He received the Nobel Prize for physics in 1903 “for his discovery of spontaneous radioactivity.” At the same time, half of the prize for that year was conferred on the Curies. In addition to the Nobel Prize, he received other awards such as the Bernard Award, and Helmholtz Award. In 1900 Becquerel received the Rumford Medal for his discovery of the radioactivity of uranium and the Légion d’ Honneur decoration was conferred on him.
He was a member of the Academy of Sciences, became its president, and was elected to the far more influential post of permanent secretary. He held three chairs of physics in Paris - at the Museum of Natural History, at the École Polytechnique, and at the Conservatoire National des Arts el Métiers - and attained high rank as an engineer in the National Administration of Bridges and Highways (Ponts et Chaussées).
Several discoveries have also been named after Becquerel, including a crater called “Becquerel” both on the moon and Mars and a mineral called “Becquerelite” which contains a high percentage of uranium by weight. The SI unit for radioactivity, which measures the amount of ionizing radiation that is released when an atom experiences radioactive decay, is also named after Becquerel: it's called the becquerel (or Bq).
In his religious affiliation, Henri Becquerel was a Roman Catholic.
Becquerel was elected a member of the Academie des Sciences de France in 1889 and succeeded Berthelot as Life Secretary of that body. He was a member also of the Accademia dei Lincei and of the Royal Academy of Berlin, amongst others.
Quotes from others about the person
"I have to keep going, as there are always people on my track. I have to publish my present work as rapidly as possible in order to keep in the race. The best sprinters in this road of investigation are Becquerel and the Curies..." — Sir Ernest Rutherford
"Who would not have been laughed at if he had said in 1800 that metals could be extracted from their ores by electricity or that portraits could be drawn by chemistry." (Commenting on Becquerel’s process for extracting metals by voltaic means) — Michael Faraday
In 1874, Henri married Lucie Zoé Marie Jamin, who would die giving birth to her son. His son was named Jean Becquerel and he went on to become a scientist as well. Jamin died in1878. In 1890 Henri Becquerel married Louise Désirée Lorieux.
1878–1953
